1. Field of the Invention
One aspect of the present invention relates to an electronic apparatus including a rotatable or slidable display unit.
2. Description of Related Art
Recently, in accordance with reduction in the size and the weight of an electronic apparatus and improved performance in its signal receiving/transmitting function, the electronic apparatus having a data communication function and a video viewing function have been widely spread. A cellular phone, that is, an example of the electronic apparatus having such functions, is capable of voice communication and data communication by using a radio communication function. Cellular phones having the radio communication function are conveniently used in various fields of telephone communication, receiving/sending e-mails, browsing websites on the Internet and commodities transaction utilizing Internet shopping. In accordance with increase of the applications of such cellular phones and increase of information quantity dealt with by the cellular phones, there is a demand for development of a cellular phone in which information displayed on its screen may be more easily recognized.
Furthermore, cellular phones having a television view function through a one-segment broadcasting service, that is, one type of the video viewing function, have recently been put to practical use. Also in such a cellular phone displaying a television image, there is a demand for a screen that may be more easily viewed.
Incidentally, a related-art cellular phone has a vertical casing so that a user can easily hold it, and is equipped with a display screen in a similar vertical arrangement. In such a cellular phone including a vertical display screen, however, a text is difficult to read in displaying text information because only a small number of characters are displayed in one line. Furthermore, in displaying a video on the screen by using the aforementioned television view function or the like, the displayed image is small because the video delivered in a landscape format is displayed on the vertical screen, and thus, visibility is spoiled.
In order to overcome such a problem, a cellular phone in which a casing having a display screen is rotatable by 90 degrees against a main body of the cellular phone has been put to practical use. When the cellular phone is not used, the casing having the display screen is placed in a vertical state, and in, for example, reading an e-mail or viewing a video, the casing having the display screen is rotated. In this manner, the main body of the cellular phone is in a vertical shape easily held, and at the same time, the cellular phone can be used with the display screen rotated into a landscape shape for easing the view of text information and a video.
Japanese Laid-Open Patent Publication No. JP-A-2008-278226 discloses a cellular phone in which the casing having the display screen is provided along a surface direction, to face front of the cellular phone so that the casing having the display screen may be slidable along the lengthwise direction of the main body of the cellular phone, furthermore, in which a casing having a display screen is rotatable by 90 degrees against a main body of the cellular phone from a state where the casing having the display screen is slid. As alternative related art, Japanese Laid-Open Patent Publication No. JP-A-2008-67335 discloses a cellular phone in which a casing having a display screen is rotatable against a main body of the cellular phone by 90 degrees in the rightward or leftward direction. The casing having the display screen is provided with a magnet, and a magnetic sensor is provided in a position opposing the magnet when the casing having the display screen is rotated. In JP-A-2008-67335, a technique to detect the rotation state of the casing having the display screen by detecting a voltage or a current generated when the magnetic sensor and the magnet come close to each other has been proposed.
In a cellular phone that can be in any of a plurality of states as described in JP-A-2008-278226, when a structure, for example, that a casing having a display screen is slid and further rotated by 90 degrees against a main body of the cellular phone is employed, the cellular phone can be in any of three states, that is, a closed state where the casing having the display screen is not slid, an opened state where the casing is slid and a T-shaped state where the casing is slid and further rotated by 90 degrees. In order to detect such a plurality of states, it is necessary to provide a plurality of magnets and magnetic sensors respectively corresponding to the states within the cellular phone. When a large number of magnets and magnetic sensors are provided within the cellular phone, however, the number of components and lines included therein is disadvantageously increased, so that the downsizing of the cellular phone is prevented.